Conventionally, switching networks have been made up of a plurality of switching matrix stages. Such switching networks known in the state of the art suffer from numerous drawbacks. Generally, they run the risk of blocking, i.e. there is a risk that it can be impossible to find a path between bothway I/O links both possessing the passband required for establishing a given connection.
If it is desirable to avoid such risks of blocking, then the intermediate stages of such known networks must be numerous and they must include high numbers of switching matrices and of links between the matrices. Such networks are therefore expensive in matrices and in links between matrices.
Because of the high number of stages to be passed through, the time required for switching between two bothway I/O links is long.
Furthermore, such known networks make routing complex because of the plurality of potential paths that exist between two bothway I/O links.
In addition, to accommodate traffic unbalances, such known networks require traffic to be distributed.
Finally, the enlargement or "growth" of known networks requires at least partial rewiring of the component elements of the network that is to be enlarged. In other words, known networks are not easily extended.